This invention relates to a ladder (which may be a step ladder) of which the stiles and the steps are provided by a single-piece coherent metal sheet which is divided between the individual steps, transversely to the stiles, and in which, furthermore, the steps are twisted out of the plane of the metal sheet, the twisted portions having a lesser depth than the depth of the step and the stiles are formed by profiling of the flat material.
Such a ladder is already known from German Offenlegungsschrift No. 2404108. When using this ladder it becomes evident that, in order to achieve the necessary torsional rigidity and strength, disporportionately strong or thick sheet metal has to be used, which in turn means that there has to be a very high investment expenditure for the heavy machines necessary for production of the ladder. Furthermore, the ladders produced from the thick sheet material become very heavy, so that they are generally suitable only for stationary use.
However, the need exists of producing ladders which are light in weight and suitable for mobile use, similarly from a single-piece metal sheet, by the use of comparatively thin metal sheet or light metal sheet.